Method and apparatus for reducing tubing



' S. D. INSCHO METHOD AND APPARATUS FOR REDUCING TUBING Aug. 25, 1936.

Filed May 26, 1.934

Patented Aug. 25, i936 BETHOD AND APP ATHIS FR REDUCING TUBING Sidney D.. Inscho, Shelby, Ohio Application May 26, 1934, i

' 1i claims. (ci. sos-n n In my copending application Serial No. 793,821, led December 23, 1933, I have descri the making of tubular products by progressively weakening local portions of a tubular blank and progressively stretching the locally weakened portions' to elongate and reduce the same permanently a predetermined amount. ln accordance with the preferred practice. described therein. a local portion of the blank is heated to weaken the same and the bl is subjected to a. stretching action to elongate and reduce the weakened portion. Proceeding acent the initially weakened portion, other local portions of the blank are heated and weakened propres@ sively throughout substantially the entire length ci the blank and these weakened portions are elongated and reduced progressively by stretchn ine.

The present application is la continuation in part of my said copending application and also i contemplates the elongation and reduction of a blank by progressively weakening adjacent local portions and progressively elongating the irreale ened portions by stretching. In accordance with an important aspect of the present invention, a local mrtion of the blank @rst is rendered ive-a er than the remaining portions, prei'ely. by heating to a higher temperature. The :t then is subjected to a stretching action to elongate 3@ and reduce the weakened portion a predetermined amount and cause an adjacent rtion to he weakened by being elongated and mduced to a lesser extent. The stretching action un the blank is continued to cause the newly weakened portion to be elongated and reduced a predetermined amount and to cause a rtion acont thereto to be weakened. action is con tinued to cause adjacent local portions ot the blank to be weakened pressively and to be 4o elongated and reduced progressively a predetermined amount. In the manufact of tubular metal products, the inner dieter of the ished product is limited by a man itioned within the tubular blank..

The invention will he more clearly understood from the following description in conjunction with the accompanying drawing: in which,

Fig. l is a longitudinal elevational view, partly broken away, of an apparatus for the practice oi so the invention;

Fig. 2 is an end elevational view, as viewed from the left ol Fig. l; and

Figs'. 3, e, and 5 are diagrammatic views. partly in section, illustrating the action which tuig@ so place during the practice oi the invention.,

Before explalnirm in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the in- 5 vention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the pur-1 pose of description and not of limitation, and it is l0 not intended to limit the invention claimed herein beyond the requirements of the prior art.

A suitable apparatus for the practice of the invention as illustrated in thel accompanying drawing comprises spaced parallel l-beams i@ 15 and il suitably secured upon spaced supports i2, mand it. Supports it, it and il extend between and are secured to the I-oearns i@ and il by bolts ill at each end thereof and midway between the ends thereof. Bearings it, it, and 2@ 2i are secured upon the supports it, it, and il by bolts il and lare adapted to rotatably support a screw shaft 2s having oppositely threaded sections ii and 25. Collars 26 "and 2l are suitably lined upon the screw shaft 2? so as to engage op- 25 posite ends of the hearing i9 to prevent axial movement of the screw shaft. Pulling heads to and di are each provided with guides 32 extendiria' laterally from opposite sides thereof so as to slidably engage the top surfaces of the I-loeanis 30 id and il. The pulling heads 30 and lli., are provided with depending portions 3d and 35 having threaded openings adapted to engage the threaded sections 2t and 2s respectively of the screw shaft it. The pui heads 3i! and si are adapt- 35 to grip opposite ends of a tubular metal blank B lto move the ends outwardly away from one another and to move relative to a mani tt po1 sltioned within the plank B. A gear is is suitably uned upon the screnr shaft 23 and is adapted 4o engage opinion tu fined upon the armature shalt ot a motor di which is suitably secured upon a support el. Means are' also provided. such' as a heating torch llt, for heating e local portion of the blank E initially, as indicated at o, 45 to a temperature higher than the remaining por tions of the bl.

In e production of e. seamless metal tube, the tubular blank B is placed over the mandrel El and one end of the plank is gripped by the pulling 5o head 3d and the other end is gripped by the pulling head il. Preferably, the entire blank is heated to reduce its tensile strength and this may be accomplished by heating either before or alter the bla has heen placed in the pulling wir to 55 and il i. The local portion a is now heated by the torch 33, as indicated in Figs. 1 and 3, to a higher temperature to render it weaker than the remaining portions of the blank and the torch is removed. Power is supplied to the motor di to rotate the screw shaft 23 and move the .if heads 30 and di outwardly away from one another to subject the blank to a stretching action and cause the weakened portion o to elongate and reduce in diameter until it comes in contact with the mandrel 38 and to elongate and reduce to a lesser extent the adjacent portions b and c adiacent thereto as indicated in Fig. 4. After contact with the mandrel stretching of the previously weakened portion ceases and it is held stationary with the mandrel. By elongating and reducing portions b and c in this manner, they are rendered weaker than the remaining unreduced portions of the blank. As the pulling heads 30 and Si continue to move away from one another, the portions b and c are elongated and reduced until they are brought into contact with the mandrel 38 and at the same time the portions d and e are elongated and reduced to a lesser extent, as indicated in Fig. 5, thereby rendering the portions d and e weaker than the remaining unreduced portions ofthe blank. By continuing movement of the pulling heads 30 and 3i outwardly away from eachother in this manner, the local portions of the blank are weakened and elongated progressively toward the opposite ends of the blank. After the stretching operation has been completed, the unreduced end portions where the blank has been gripped by the pulling heads 30 and 3| are out oil. The tube may be expanded in any well known manner to relieve it so that the mandrel can be withdrawn as byrunning through cross rolls.

It will be understood that in the preferred practice, as illustrated, the pulling heads move outwardly away from one another at substantially equal rates and each will travel a distance equal tothe ilnal distance between the rst and last local portions of theblank elongated and reduced minus the initial distance between the ilrst and last local portions of the blank elongated and reduced. In other words, disregarding the portions of the blank which are gripped by the pulling heads 30 and 3i and which are not elongated and reduced by stretching, the pulling heads will move a distance equal to half the length of the nished tubular product minus half the length of the original blank. The mandrel controls the amount of reduction and elongation and, consequently. the wall thickness and inner diaizneter of the finished tubular product. What I claim is:

l. Themethod which comprises heating a tubular blank, heating an intermediate portion of the blank to ahigher temperature to render the same weaker than the remaining portions, subiecting said blank to a stretching action to cause acid weaker portion to neck down and be elongated permanently and cause adjacent portions at opposite sides thereof to be weakened progressively and to draw down and be elongated progressively and permanently, and controlling the amount of pecking and drawing down and elongation of said portions by means of a mandrel within the blank.

2. 'I'he method which comprises the steps of heating a tubular metal blank to render one portion thereof weaker than the remaining portions, and applying opposed forces to opposite ends of the blank to move one end relative to the other asesoria end to cause said weaker portion to be elongated permanently and cause adjacent portions of the blank at opposite sides of said weaker portion to be weakened progressively and elongated progressively and permanently, and internally controlling the amount of elongation of said portions.

3. The method which comprises the steps of heating a tubular blank to render one portion thereof weaker than the remaining portions, and moving each end of the blank outwardly away from said-weaker portion to elongate said portion and cause adjacent portions of the blank to be weakened progressively and elongated progressively and permanently, and controlling the amount of elongation of said portions by means of a mandrel within the blank.

4. The method which comprises the steps of heating a tubular metal blank to render one portion thereof weaker than the remaining portions, and moving each end of the blank outwardly away from said weaker portion at substantially equal rates to elongate said portion -and cause adjacent portions of the blank to be weakened progressively and elongated progressively and permanently, and internally controlling the amount of elongation of said portions.

5. A method of elongating a tubular metal blank and reducing its diameter which comprises slightly lowering the strength of the metal in a short section of the blank, stretching the blank to cause that section to neck down and elongate, applying internal pressure to the center of that section as soon as its bore is reduced to a predetermined diameter to prevent its further neckf ing down and elongation, continuing to stretch the blank to cause the weakened tapered sections at the ends of the neck at each side of the short section ysupported by internal pressure to draw down and elongate, applying internal pressure 'to those sections as soon as their bore is reduced to a predetermined diameter, and continuing to stretch the blank to cause successive sections to draw down and elongate, the drawing down and elongation of each section being stopped by the application of internal pressure when its bore reaches a predetermined diameter.

6. A method of elongating a tubular metal blank and reducing its diameter which comprises heating vthe entire blank to a uniform high tem` perature, heating a short section to a Slightly higher temperature, stretching the blank to cause that section to neck down and elongate, applying internal pressure to the center of that section as soon as its bore is reduced to a predetermined diameter to prevent its further necking down and elongation, continuing to stretch the blank to cause the weakened tapered sections at the ends of the neck at each side of the short section supported by internal pressure to draw down and elongate, applying internal pressure to those sections as soon as their bore is reduced to a predetermined diameter, and continuing to stretch the blank to cause successive sections to draw down and elongate, the drawing down and 05 blank to a stretching action to cause said weaker portion to be elongated permanently and cause adjacent portions to be weakened progressively and elongated progressively and permanently, and means for internally controlling the elongation of said portions.

8. An apparatus for making a tubular product which comprises heating means adapted to subject a tubular blank to heat for a sulcient time to render one portion thereof weaker than the remaining portions and thereafter be moved away from the blank, means for subjecting the blank to a stretching action to cause said weaker portion to be elongated permanently and cause adjacent portions to be weakened progressively and elongated progressively and permanently, and means for limiting the inner diameter of said product.

9. An apparatus for making a tubular product which comprises heating means adapted to subject a tubular blank to heat for a sufcient time to render one portion thereof weaker than the remaining portions and thereafter be moved away from the blank, means for subjecting the blank to a stretching action to cause said weaker portion to be elongated permanently and cause adjacent portions to be weakened progressively and elongated progressively and permanently, and means for controlling the elongation of said portions and limiting the inner diameter of said product.

10. An apparatus for making a tubular product which comprises means adapted to act upon a portion of a tubular blank to render the same weaker than the remaining portions, means for moving the ends of said blank in opposite directions, and a mandrel for controlling the inner diameter of said product.

1l. An apparatus for making a tubular product which comprises means adapted to act upon a 40 portion of a tubular blank to render the same weaker than the remaining portions, and means for moving the ends of said blank at substantially equal rates in opposite directions, and a mandrel for controlling the inner diameter of said tubular product.

12. An apparatus'for making a tubular product which comprises means adapted to act upon a portion of a tubular blank to render the same weaker than the remaining portions, af rotatable screw shaft held against axial movement and having left and right hand threads, means operatively associated with said left hand threads adapted to grip one outer end of the blank, means operatively associated .with said right hand threads adapted to grip the other outer end of the blank, and a mandrel for controlling the inner diameter of said tubular product.

13. An apparatus for reducing the diameter of and elongatlng tubes, comprising a mandrel smaller in cross-section than the bore of the tube and over which the tube is adapted to be placed, means for grasping the tubev at two points spaced along the length of the tube, removable means for making a short section of tube between the grasping means hotter than the rest of the tube between the grasping means, and means for moving oneof the grasping means away from said section.

14. An apparatus for reducing the diameter of and elongatlng tubes, comprising a mandrel smaller in cross-section than the bore of the tube and over which the tube is adapted to be placed, means for grasping the tube at two points spaced along the length of the tube, means for making a. short section of tube between and spaced from both grasping means hotter than the rest of the tube between the grasping means. and means for moving both grasping means away from said section.

SIDNEY D. INSCHO. 

